As represented by trolley buses, there have been proposed current-collecting electric drive vehicles, each of which runs using power supplied from overhead wires in an area equipped with the overhead wires but runs by drive power from an internal combustion engine in an area equipped with no overhead wires (see Patent Document 1).
On the other hand, such current-collecting dump trucks are also used as dump trucks that haul ores dug by excavators at a mine. In an area equipped with overhead wires, each dump truck (electric drive vehicle) of this type runs by driving an electric motor with power supplied from the overhead wires, but in an area equipped with no overhead wires, runs by driving a generator with an engine (for example, diesel engine) and driving the electric motor with power generated by the generator. Hereinafter, the mode in which running is performed using power supplied from overhead wires will be called “the trolley mode”, while the mode in which running is performed by driving a generator with an engine and using power generated by the generator will be called “the diesel mode”. In general, the trolley mode is high in running speed and can increase the transport volume, because the power to be supplied to an electric motor is greater in the trolley mode than in the diesel mode. Further, the trolley mode is lower in fuel consumption compared with the diesel mode because the trolley mode needs no engine output. In a mine, a plurality of such dump truck are running while switching the trolley mode and the diesel mode depending on the running area.